1. Field of the Invention
The present invention relates to a control apparatus for a internal combustion engine installed on a vehicle, and in particular, to a control apparatus for an internal combustion engine in which the stability of the operating state of the internal combustion engine is improved by controlling a rotating electrical machine connected to the internal combustion engine for both electric driving and electric power generation.
2. Description of the Related Art
Conventionally, there has been proposed a control apparatus which serves to suppress the variation of the rotational speed of an internal combustion engine by using a rotating electrical machine connected to the internal combustion engine installed on a vehicle for electric driving as well as electric power generation.
In general, the conventional control apparatus for an internal combustion engine controls the generated torque of the rotating electrical machine so as to counteract the rotational fluctuation of the internal combustion engine by switching the operating state of the rotating electrical machine between an electrically operating or driving state and a power generation state (see, for example, a first patent document: Japanese patent No. 2617936).
In the conventional apparatus as described in the above-mentioned first patent document, in order to suppress the rotational fluctuation of the internal combustion engine (i.e., to suppress the generated torque), the operating state of the internal combustion engine is switched between the electrically operating state and the power generation state thereby to generate torque pulsating in a direction opposite to that of the rotational fluctuation of the internal combustion engine.
At this time, the average value of the output of the rotating electrical machine becomes an amount of electric power generation for supplying an amount of output corresponding to the amount of load of the vehicle. Here, note that a power supply system (e.g., a battery, a capacitor, etc.) is connected to the rotating electrical machine.
In the conventional control apparatus for an internal combustion engine, no consideration is given to the charged state of the power supply system connected to the rotating electrical machine, so in case where the charged state of the power supply system is a full charged state, the power supply system becomes an overcharged state when the amount of electric power generation of the rotating electrical machine becomes larger than the electric power load of the vehicle, as a result of which there is a problem of causing adverse influences such as a reduction in service life, etc., to the power supply system.